I found two other postings on this problem, but neither of them had a posted solution. I am trying to create a union query that joins 21 tables together. Parts of it were working fine, but the completed query doesnt work. It just gives me the error "Not a valid alias name" when i try to view it in a datasheet. I have no clue whats wrong with it because, as i said before, individual parts of it work just fine. I have tried taking out different tables to see if it would work, and no matter which table is omitted it works fine. Why does every combination of 20 tables (i tried about 10)work, but they wont work when put together?